Two Algorithms For Image Processing Based On Chaos And Fractal

Today with the development of modern information science, technology and Internet applications, a large number of digital information in various forms has been transmitted quickly and conveniently through the network moment by moment. This makes the requirements of information security and data transmission are also increasing. In this paper, based on the knowledge of fractal and image compression and chaotic dynamics, several application methods about image compression and encryption are proposed.Since the conception of digital TV was proposed in 1948, image compression technology has developed rapidly. Image compression has been after two phrases of development: the first is based on DCT, especially at high compression ratio, exhibit highly noticeable blocking artifacts. The second represented by image compression based on Wavelet transform. The image compression based on fractal has a high theoretical value because of its desirable properties such as fast decoding, high compression ratio and resolution independence of decoded image. This paper proposes a image compression based on combing Fractal and wavelet transform. To improve the quality of image after the restoration, according to the properties of wavelet transform sub-bands, we apply the fractal coding to the decomposed high-level subband image and construct the low-level with the ones. On the one hand, it can use the correlation between the images; on the other hand, it can reduce the data needed for reconstruction image effectively.Chaotic system has serials excellent cryptographic properties, such as randomness, the sensitivity of the initial value and the noise-like broadband frequency spectrum. Using the chaos theory to implement secret communication has been a new technology of the image encryption. In this paper a new chaotic theory was proposed: first initialize the image by making use of compressed sensing based on wavelet transform, then using skew tent map combining system of sine iterate for image encryption, which is not only reduce the time of encryption but also lowering the difficulty of calculation. The results compare with the traditional skew tent map sequence encryption algorithm; it greatly enhances the security of image encryption in the image without distortion.